Question

1. The value of (1/1 + cos A) + (1/1 - cos A) is?
A. 2(sec A)^2 B. 2sec A C. 2(cosecA)^2 D. 2cosec A

2. The value of (tan A)^2 + (tan A)^4 =
A.(sec A)^4 - (sec A)^4 B. (sec A)^2 - (sec A)^4
C. (sin A)^2 - (cos A)^2 D. (sec A)^2 - (tan A)^2

Answer 1

heya..!!!!

_________________(1)_________________

1/(1 + cosA) + 1/(1 - cosA)

=> (1 - cosA + 1 + cosA)/(1 + cosA)(1 - cosA)

=>2/(1 - cos²A)

=> 2/sin²A

=> 2cosec²A

HENCE, option (A) is correct

________________(2)_________________

tan²A + tan⁴A

=> tan²A(1 + tan²A)

=> (sec²A - 1)( sec²A - tan²A + tan²)
[ sec²A - tan²A = 1]

=> (sec²A - 1)(sec²A)

=> sec⁴A - sec²A

HENCE, option (A) is correct